package com.example.demo.interceptor;


import com.auth0.jwt.JWT;
import com.auth0.jwt.exceptions.JWTDecodeException;
import com.example.demo.annotation.PassToken;
import com.example.demo.annotation.UserLoginToken;
import com.example.demo.utils.JwtHelper;
import org.springframework.web.method.HandlerMethod;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.lang.reflect.Method;

public class AuthenticationInterceptor implements HandlerInterceptor {

    public boolean preHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object object) throws Exception {

        String token = httpServletRequest.getHeader("token");// 从 http 请求头中取出 token
        System.out.println("token: " + token);
        // 如果不是映射到方法直接通过
        if(!(object instanceof HandlerMethod)){
            return true;
        }

        HandlerMethod handlerMethod=(HandlerMethod)object;
        Method method=handlerMethod.getMethod();

        //检查是否有 PassToken 注解，有则跳过认证
        if (method.isAnnotationPresent(PassToken.class)) {
            PassToken passToken = method.getAnnotation(PassToken.class);
            if (passToken.required()) {
                return true;
            }
        }

        //检查有没有需要用户权限的注解
        if (method.isAnnotationPresent(UserLoginToken.class)) {
            UserLoginToken userLoginToken = method.getAnnotation(UserLoginToken.class);
            if (userLoginToken.required()) {
                // 执行认证
                if (token == null) {
                    throw new RuntimeException("无token，请重新登录");
                }


                // 验证是否是登录状态
                boolean verifyResult = JwtHelper.verify(token);
                if(!verifyResult) {
                    throw new RuntimeException("token失效,请重新登录");
                }

                // 获取 token 中的权限 access
                String access;
                try {
                    access = JWT.decode(token).getClaim("access").asString();
                } catch (JWTDecodeException j) {
                    throw new RuntimeException("获取token中的权限错误");
                }
                if(access.equals("super_admin")) {
                    return true;
                } else {
                    throw new RuntimeException("无权限操作");
                }
            }
        }

        return true;
    }

    @Override
    public void postHandle(HttpServletRequest httpServletRequest,
                           HttpServletResponse httpServletResponse,
                           Object o, ModelAndView modelAndView) throws Exception {

    }
    @Override
    public void afterCompletion(HttpServletRequest httpServletRequest,
                                HttpServletResponse httpServletResponse,
                                Object o, Exception e) throws Exception {
    }
}
